#include <stdio.h>

int main()
{
    int num = 10;
    int *ptr, *ptr2;

    ptr = &num;
    ptr2 = ptr;

    printf("%d\n", *ptr);
    printf("%d\n", *ptr2);

    *ptr2 = *ptr2 - 1;
    printf("%d\n", *ptr);

    return 0;
}